UNi Xonar driver cleaner – Standalone driver cleaner based on the one that’s included in UNi Xonar drivers. Xonar Restoree Extended – Tool to restore Xonar cards hardware ID. The extended version includes support for Xonar STX II and Xonar DG SI cards.
I have the Essence ST. It was released after the STX and claims to reduce clock jitter more than the STX. The ST uses a PCI slot and the STX is PCIe. Most at Head-Fi that have heard both cards prefer the ST. I also have the daughtercard for the ST and use mine in a 7.1 configuration. River Media Center for bass management, distance settings, level settings, and parametric EQ so I output directly to my amplifiers. I am using my card with Windows 74 x64.
When using ASIO output the card has automatic bit-matching with the current beta drivers. I use the and like them better. They offer lower latency and fix some issues with ASIO. I did not like the standard opamps (they were too harsh) and have changed mine out.
I can't recall off the top of my head what is in there right now. The card is extremely detailed and has a great soundstage. I don't know how much you have to spend to get something better, but I've heard the Benchmark DAC (with the same music) and I prefer the Essence ST. I agree with Amir about the computer you use.
Stereophile used two different computers and different OS's for their 'comparison' of the STX and ST. I don't think the ST was getting the best computer for its capabilities in the testing. I use a Gigabyte motherboard due to their PCB design and components. I also use a Corsair 850 Watt power supply due to its exceptionally low ripple on the 5 volt rail. The Essence ST and STX both use their own power input for the audio output section.
This allows them to draw power directly from the power supply rather than having it go through the motherboard. My HTPC is a little over a year old so most components aren't available anymore. Here is what is in it: Motherboard - CPU - Intel i5-750 Memory - G Skill ECO Series 4 GB DD3 1600 Hard Disks - Two Intel X-18 80GB SSD's Blu-ray Drive - LG 8X Blu-ray Reader/DVD Burner Video Card - XFX HD5770 (underclocked with fan at lowest setting) Power Supply - CPU Cooler - Scythe Big Shuriken SCBSK-1000 120mm Case - OS - Windows 7 x64 Media Player - J River Media Center V16 Fan Control Software - Speedfan (I only have a case intake fan & CPU Fan - no exhaust fans. Both can be shut off completely.). The Win mixer by design converts all audio to 32 float for processing and back to integer (16 or 24) depending on the word length of the DAC. All audio is dithered. WASAPI and ASIO both bypass the mixer.
This is the trick to get bit perfect output. In general using these drivers improves sound quality. Part of the bit perfect game is automatic sample rate switching.
In general soundcard + WASAPI won’t do this. Soundcard + ASIO allows for automatic sample rate switching. What you need is a media player like JRiver, Foobar, etc allowing you to select these drivers. In your case ASIO is probably the best bet. MediaMonkey just released version 4.0 (November 16, 2011), and it looks like it will have support for both WASAPI and ASIO.
Asus Xonar Stx Drivers
I need to wait for my upgrade email (lifetime member), which should arrive within the next few days. This is good news for me as I really like MediaMonkey and their customer support is terrific as well! I'll keep you posted after the upgrade is done and my Asus Xonar is installed.
Asus Xonar Essence Stx Drivers
One more piece left and that is the KRK Rokit 6 active monitors. Hopefully by Xmas! (crosses fingers).